This invention relates to a method of producing a shaped article from a liquid curable resin, and to a mold therefor.
1. Description of the Prior Art
The compressive strength, tensile strength and other properties of shaped articles molded from liquid curable resins can be improved by incorporating fillers, reinforcing agents and the like in the molding composition. Moreover, such filled and/or reinforced resin articles are highly resistant to acids and other chemicals. It is for these reasons that such articles have found application in a variety of fields. However, in the production of such shaped articles from a liquid curable resin, the conventional molds made of metal, rubber, wood or FRP present problems upon ejection of the article from the mold so that heretofore, it has been difficult to produce a shaped article having a satisfactory and even surface gloss in one operation. For overcoming the above disadvantages, it has, for instance, previously been proposed to apply a mold release agent such as wax, polyvinyl alcohol, a silicone or fluorocarbon resin or the like to the casting surface of the mold or to employ a mold made of silicone rubber with or without application of a mold release agent. However, since none of the prior art methods insures satisfactory release of the article, the article cannot be casily taken out from the mold. Moreover, in the event that the article is partially released in an early stage of the curing process, it assumes an uneven surface gloss. It has thus been difficult to obtain a shaped resin article with a satisfactory even surface gloss.
Therefore, it heretofore has been necessary, in order to obtain a shaped article having a satisfactory even gloss, to buff or coat the surface of the molded articles or apply a gel coating which contains little or no filler to the surface of the mold. However, these methods not only add to the production cost of the articles but when coating or gel coating is employed, the resin layer on the surface of the article detracts from the surface hardness and strength of the article.